Aliphatic polyester resin composition and sheets, films or other products molded by the resin

ABSTRACT

Provided is a thermoplastic resin composition, in particular, an aliphatic polyester resin composition comprising a plasticizer which is soft, exhibits high transparency, is reduced in bleeding out and exhibits high resistance to the extraction by a paraffinic solvent; and a sheet, a film or a molded article formed from the thermoplastic resin composition. An aliphatic polyester resin composition, characterized in that it comprises 100 parts by mass of an aliphatic polyester and, as a plasticizer, 1.0 to 100 parts by mass of a specific ester compound which is an ester formed from a trivalent polyhydric alcohol and an acyl group derived from a carboxylic acid having 2 to 18 carbon atoms and has an average acylation degree of 50 to 90%.

BACKGROUND OF THE INVENTION

1. Field of the invention

The present invention relates to an aliphatic polyester resincomposition containing plasticizers, and sheets, films or other productsmolded by the resin.

2. Description of the Background Art

In recent years, attention has focused on biodegradable plastics whichreduce environmental load as a result of increased awareness regardingproblems to the human body and natural environment. Examples ofbiodegradable plastics on which attention has been focused include analiphatic polyester. Though a polylactic acid as the aliphatic polyesteritself is an inherently brittle resin, however flexibility can beapplied by adding plasticizers thereto. The application development ofpolylactic acid has been briskly performed in recent years, and variousnovel plasticizers capable of being used for the polylactic acid andhaving a low environmental load have also been proposed.

Though triethylene glycol diacetate, glycerin triacetate, glycerintripropionate, tributyl acetylcitrate, etc., have been known asplasticizers which apply flexibility with the transparency of thepolylactic acid maintained (for example, refer to Patent Reference 1),any of plasticizers and polylactic acid are not sufficiently compatible.When applications to various uses are actually attempted, the increasein the amount of additional plasticizers causes intense bleed outgenerated from the resin of the plasticizers before obtaining sufficientflexibility, and thereby the increase is not suitable for practical use.

Though a producing method of stretched film made of flexible aliphaticpolyester by adding a diaceto monoglyceride fatty acid ester and apolyglycerol monoaliphatic ester as the plasticizer which does not bleedhas been known (for example, refer to Patent Reference 2), when theapplication to a packaging material is attempted using the compositionof this technique, sufficient flexibility and transparency are acquired.However, there is a problem that the amount of elution of theplasticizers is large in an elution test due to a paraffin solvent, andcorrespondence is further desired on a use condition where theplasticizers come into contact with oily food.

The present inventors have previously proposed the use ofdiacetomonoglyceride fatty acid ester and polyglycerin acetic acid esteras the plasticizers (for example, refer to Patent Reference 3). However,also in the composition, the problem of a shift of the plasticizers tofood has not been completely solved.

-   Japanese Published Unexamined Patent Application No. Hei-11-323113-   Japanese Published Unexamined Patent Application No. 2000-302956-   Japanese Published Unexamined Patent Application No. 2003-73532

DISCLOSURE OF THE INVENTION

The present invention has been accomplished in view of the aboveproblems in the prior art. Accordingly, it is an object of the presentinvention to provide a thermoplastic resin composition which contains aplasticizer having flexibility, high transparency, little bleed out andhigh extraction resistance to a paraffin solvent, particularly analiphatic polyester resin composition, and a sheet, film, or moldedproduct molded from the same.

The present invention has the following composition so as to attain theabove object.

1. An aliphatic polyester resin composition contains a compound (A) of1.0 mass part to 100 mass parts expressed by the following formula (1)as a plasticizer to an aliphatic polyester of 100 mass parts.

In the formula, X denotes a trivalent polyalcohol frame; R¹, R², R³ areselected from an acyl group having 2 to 18 carbon atoms or a hydrogenatom; the sum total of carbon numbers of R¹, R², R³ is 10 to 22; and theaverage acylation rate is 50 to 90%.

2. The aliphatic polyester resin composition according to the item (1),wherein R¹, R², R³ of the formula (1) contain at least one acyl grouphaving a carbon number of 8 to 18.

3. The aliphatic polyester resin composition according to the item (1)or (2), wherein the aliphatic polyester resin is a lactic acid systempolyester.

4. Sheets, films, or other products molded from the aliphatic polyesterresin composition described in any one of the items (1) to (3).

The present invention can provide effects enumerated below.

(1) The plasticizer is edible, and even when the plasticizer is used asa food packaging material, the safety of the plasticizer is very high.

(2) The plasticizer has excellent plasticization performance, and aflexible aliphatic polyester resin composition can be obtained.

(3) A resin composition having little inhibition of transparency andbleed can be obtained.

(4) The sheet, film or molded product using the aliphatic polyesterresin composition of the present invention has high solvent resistanceto a paraffin solvent, and the sheet, film or molded product has littleshift of the plasticizer to food even when the sheet, the film or themolded product is used to oily food.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, the present invention will be explained in detail accordingto best mode for carrying out the invention.

A thermoplastic resin composition used for the present invention isobtained by adding the compound (A) as a plasticizer to an aliphaticpolyester.

The aliphatic polyester of the present invention is not particularlylimited, and a known aliphatic hydroxycarboxylic acid or a polymerconsisting of an aliphatic diol and an aliphatic dicarboxylic acid canbe used. Each of aliphatic hydroxycarboxylic acid, aliphatic diol andaliphatic dicarboxylic acid to be used may be a copolymer using aplurality of kinds. Examples of the aliphatic hydroxycarboxylic acids inthe present invention include a lactic acid, a glycolic acid,ε-caprolactone and 3-hydroxy butanoic acid. Examples of the aliphaticdiols include ethylene glycol, polyethylene glycol, propylene glycol,butylene glycol, 1,4-butanediol, 1,6-hexanediol and neopentyl glycol.Examples of the aliphatic dicarboxylic acids include a succinic acid, anadipic acid, an azelaic acid, a sebacic acid, a dodecanedioic acid, amaleic acid and a fumaric acid. Of these, the aliphatic dicarboxylicacid including a lactic acid unit in a molecule is preferable in view ofthe property and biodegradability of the resin. It is preferable thatthe aliphatic polyester of the present invention contains the lacticacid unit of 30 mol % or more, and particularly preferably 50 mol % ormore. The lactic acid used for aliphatic polyester of the presentinvention may be a D isomer or an L isomer.

The lactic acid system polyester preferably used for the presentinvention has a crystalline thermoplastic polymer having tensilestrength equivalent to that of polyethylene and transparency equivalentto that of polyethylene terephthalate. The lactate polyester is used forsutures, etc., for medical purposes, and has high safety. In addition,when the lactate polyester is burned, the combustion calorie is aboutone third of those of polyethylene and polypropylene, etc., and anincinerator is not damaged by the combustion. Also, no harmful gas isgenerated.

The degree of polymerization or quality of the polylactic acid resin tobe used is not considered. Not only the homopolymer of the polylacticacid but also a copolymer such as glycolic acid, c-caprolactone,trimethylene carbonate, polyethylene glycol, etc., may be used together.The other biodegradable polymer such as acetylcellulose,polycaprolactone, polybutylene succinate, a copolymer of polyhydroxybutyrate and valerate, chitin, chitosan and starch may be blended in arange where the property of the polylactic acid resin is not spoiled.

A polycarboxylic acid such as malic acid, tartaric acid and citric acid,and a polyalcohol such as glycerin, diglycerin, polyglycerin,trimethylolpropane, pentaerythritol and dipentaerythritol may bepolymerized in a range where the performance of the invention is notinhibited. Also, an isocyanate compound, an epoxy compound, an aziridinecompound, an oxazoline compound, an azo compound, a polyvalent metalcompound, a polyfunctional phosphate ester, an ester phosphate, etc.,may be used as a chain extender.

The plasticizer used for the present invention is a compound (A)expressed by the above formula (1). The compound is an ester oftrivalent polyalcohol and acyl group derived from a carboxylic acidhaving 2 to 18 carbon atoms. Though examples of trivalent polyalcoholscapable of being used in the present invention include glycerin,trimethylolpropane and hexanetriol, the glycerin is preferable in viewof the easy acquisition of the materials. Though the acyl group having 2to 18 carbon atoms capable of being used in the present invention is notparticularly limited, examples thereof include an acetyl group, apropionyl group, a butyryl group, a caproyl group, a caplyroyl group, alauryl group, a myristyl group, a palmityl group, a stearyl group and anoleyl group.

The sum total of the number of the carbon atoms of the acyl groupcontained in the compound is 10 to 22. When the sum total of the carbonatoms is less than 10, the boiling point of the compound becomes low,and thereby it is difficult to use the compound as the plasticizers.When the sum total of the carbon atoms is more than 22, the flexibilityis worsened, and the bleed out from the resin becomes intense. When therate (molar ratio) of the acyl group contained in R¹, R², R³ of theformula (1) is the average acylation rate, the average acylation rate ofthe compound should be within the range of 50 to 90% in the presentinvention, preferably 55 to 90%. When the average acylation rate ishigher than 90%, the solvent resistance to a paraffin solvent isreduced. When the average acylation rate is lower than 50%, thecompatibility with the resin is reduced, and the transparency and theflexibility are reduced. The calculation of the average acylation rateis shown in the Examples.

In the formula (1), preferable examples of the combination of carbonnumber of R¹, R², R³ include (the number of the carbon atoms of R¹, thenumber of the carbon atoms of R² and the number of the carbon atoms ofR³) of (18, 2, 0), (12, 2, 0), (10, 10, 0), (10, 8, 0), (12, 8, 0), (8,8, 0), (10, 2, 0), (8, 2, 0), (18, 2, 2), (12, 2, 2), (10, 6, 2). Theorder of the combination of R¹, R², R³ is not particularly limited, andR¹, R², R³ may be in any position. The compound is usually a mixturethereof, and the sum total of the number of the carbon atoms andacylation rate of the acyl group are the average value of the mixture.

The production method of the compound is not particularly limited, andthe compound can be produced by adjusting so that the acyl group is lessthan 3 mol to the trivalent polyalcohol of 1 mol by a known usualproducing method of ester. For example, the compound can be produced bythe ester exchange reaction of the polyalcohol and polyalcohol triacylester. The compound can also be produced by performing theesterification reaction of acyl acid or anhydrous acyl acid to thepolyalcohol and polyalcohol monoacyl ester. The mixture obtained bythese reactions thereof is distilled and recrystallized, and the sumtotal of the number of the carbon atoms of the acyl group can also beadjusted.

In the present invention, the blending amount of the plasticizer toresin is within the range of 1.0 to 100 mass parts to the resin of 100mass parts, and preferably 1.0 to 60 mass parts. When the blendingamount is less than the range, the performance is insufficient. When theblending amount exceeds the range, the bleed of the plasticizer isobserved, and thereby the performance is reduced.

In this invention, other 1 or 2 or more plasticizers can be usedtogether in the range where the effect of the present invention isspoiled. Though a stabilizer, a lubricant, an antioxidant, a slip agent,a nucleating agent, an antiblocking agent, an antifog additive, anantistatic agent, a filler, etc., are used together if needed, theseadditive agents can be used together in the range where the effects ofthe plasticizer of the present invention are not inhibited.

The resin composition of the present invention can be processed into asheet, a film and a molded product and used by the conventionally knownmethod. For example, the fatty acid polyester, the plasticizer, and theother additive agents are melted and kneaded in a strand die and atwo-axle extrusion machine provided with a liquid adding machine, andthe strand is cut, and a pellet is formed. A sheet, a film, and a moldedproduct can be respectively formed by an extrusion machine and injectionmolding machine, etc., provided with a T die or an inflation die byusing the obtained pellet. Referring to the formed film and moldedproduct, the mechanical property, heat resistance and dimensionalstability of the product can be improved by heat treatment. In such acase, the transparency and the glossiness can be improved by extensiontreatment.

Hereinafter, though the present invention will be explained in detailaccording to the Examples, the aspect of the present invention is notlimited thereto.

EXAMPLE 1

Glycerin of 920 g (10 mol), a caprylic acid of 1584 g (11 mol), a sodiumhydroxide of 2.36 g (0.06 mol) were added into a four-neck flask of 3000ml equipped with a mercury thermometer, a nitrogen introducing pipe anda stirring stick, and were reacted at 230° C. for 6 hours while flowingnitrogen at 2.0 ml/min and stirring. After the reaction end, thereaction solution was cooled to 80° C. Then, 2.36 g (0.02 mol) ofphosphoric acid aqueous solution of 85% was added, and the sediment wasremoved by depressurization filtration. The obtained reaction liquid of2400 g was put into a distillation apparatus, and depressurizationdistillation was performed at the degree of decompression of 1 Pa. Theglycerin mono caplylate of 620 g of the fraction in which thedistillation temperature is 130° C. to 150° C. was obtained. When theobtained glycerin monocaplylate was analyzed by the method to bedescribed later, the average acylation rate was 33%, and the sum totalof the number of the carbon atoms of the acyl group was 10.0.

Next, 218 g (1.0 mol) of the glycerin monocaplylate of the averageacylation rate of 33% obtained above were put into a four-neck flask of500 ml equipped with a mercury thermometer, a nitrogen introducing pipe,a back-flow pipe and a stirring stick, and were heated to 120° C. whileflowing nitrogen at 0.5 ml/min and stirring. 66 g (0.65 mol) of aceticanhydride was dropped thereto, and the mixture was reacted at 120° C.for 1 hour. After the reaction end, steam distillation was performedunder decompression to remove low boiling substances, and glycerinmonocaplylate acetic acid ester (plasticizer 1) was obtained. Table 1shows the average acylation rate of the plasticizer 1 and the sum totalof the number of the carbon atoms of the acyl group.

EXAMPLE 2

Glycerin of 276 g (3.0 mol), a capric acid of 713 g (4.1 mol), a sodiumhydroxide of 1.0 g (0.025 mol) were added into a four-neck flask of 1000ml equipped with a mercury thermometer, a nitrogen introducing pipe anda stirring stick, and were reacted at 230° C. for 6 hours while flowingnitrogen at 2.0 ml/min and stirring. After the reaction end, thereaction solution was cooled to 80° C. Then, 1.0 g (0.0083 mol) ofphosphoric acid aqueous solution of 85% was added, and the sediment wasremoved by depressurization filtration. The obtained reaction liquid of900 g was put into a distillation apparatus, and depressurizationdistillation was performed at the degree of decompression of 1 Pa. Theglycerin mono & dicaplilate of 650 g of the fraction in which thedistillation temperature is 140° C. to 230° C. was obtained. When theobtained glycerin mono & dicaprate was analyzed by the method to bedescribed later, the average acylation rate was 62%, and the sum totalof the number of the carbon atoms of the acyl group was 18.6.

Next, 382 g (1.0 mol) of the glycerin mono & dicaprate of the averageacylation rate of 62% obtained above and 65 g (0.64 mol) of aceticanhydride were reacted as in the producing example 1 to obtain glycerinmono & dicaprate acetic acid ester (plasticizer 2). Table 1 shows theaverage acylation rate of the plasticizer 2 and the sum total of thenumber of the carbon atoms of the acyl group.

EXAMPLE 3

638 g (1.0 mol) of refined coconut oil, 92 g (1.0 mol) of glycerin and218 g (1.0 mol) of triacetin were put into a four-neck flask of 1000 mlequipped with a mercury thermometer, a nitrogen introducing pipe, aback-flow pipe and a stirring stick, and 1.0 g of sodium hydroxide wasadded as a catalyst. Nitrogen was flown at 0.5 ml/min, and the obtainedsolution was heated to 250° C. while stirring. The solution was reactedat 250° C. for 2 hours. After the reaction end, the solution wasneutralized by 1.0 g of phosphoric acid aqueous solution of 85%, and thesediment was removed by depressurization filtration. The obtainedreaction liquid was put into a distillation apparatus, anddepressurization distillation was performed at the degree ofdecompression of 1 Pa. The coconut oil glycerin acetic acid ester(plasticizer 3) of the fraction in which the distillation temperature is180° C. to 220° C. was obtained. Table 1 shows the average acylationrate of the plasticizer 3 and the sum total of the number of the carbonatoms of the acyl group.

[Comparative Sample 1]

Glycerin of 920 g (10 mol), a lauric acid of 2121 g (10.5 mol), a sodiumhydroxide of 3.0 g (0.075 mol) were added into a four-neck flask of 3000ml equipped with a mercury thermometer, a nitrogen introducing pipe anda stirring stick, and were reacted at 230° C. for 6 hours while flowingnitrogen at 2.0 ml/min and stirring. After the reaction end, thereaction solution was cooled to 80° C. Then, 3.0 g (0.025 mol) ofphosphoric acid aqueous solution of 85% was added, and the sediment wasremoved by depressurization filtration. The obtained reaction liquid of2500 g was put into a distillation apparatus, and depressurizationdistillation was performed at the degree of decompression of 1 Pa. Theglycerin monolaurate of 830 g of the fraction in which the distillationtemperature is 150° C. to 180° C. was obtained. When the obtainedglycerin monolaurate was analyzed by the method to be described later,the average acylation rate was 33%, and the sum total of the number ofthe carbon atoms of the acyl group was 12.0.

Next, 274 g (1.0 mol) of the glycerin monolaurate obtained above and 37g (0.36 mol) of acetic anhydride were reacted in the same manner as inthe producing example 1 to obtain glycerin monolaurate acetic acid ester(comparative sample 1). Table 1 shows the average acylation rate of thecomparative sample 1 and the sum total of the number of the carbon atomsof the acyl group.

[Comparative Sample 2]

638 g (1.0 mol) of refined coconut oil, and 46 g of (0.5 mol) ofglycerin were reacted in the same manner as in the producing example 3.The catalyst of a reaction was similarly neutralized and filtered toremove, and coconut oil fatty acid glycerin ester (comparative sample 2)was obtained. Table 1 shows the average acylation rate of thecomparative sample 2 and the sum total of the number of the carbon atomsof the acyl group.

[Comparative Sample 3]

274 g (1.0 mol) of the glycerin monolaurate obtained by the methoddescribed in the above comparative sample 1 and 180 g (1.76 mol) ofacetic anhydride were reacted in the same manner as in the producingexample 1 to obtain glycerin monolaurate acetic acid ester (comparativesample 3). Table 1 shows the average acylation rate of the comparativesample 3 and the sum total of the number of the carbon atoms of the acylgroup.

[Comparative Sample 4]

Diacetin [commercial item (glycerindiacetate)].

Table 1 shows the average acylation rate of the comparative sample 4 andthe sum total of the number of the carbon atoms of the acyl group.

[Comparative Sample 5]

Tributyrin [commercial item (glycerintributyrate)]

Table 1 shows the average acylation rate of the comparative sample 5 andthe sum total of the number of the carbon atoms of the acyl group.

[Analysis Method]

Average Acylation Rate and Sum Total of Carbon Number of Acyl Group

A sample is methylesterified by methanol-hydrochloric acid, andmethylacylate is extracted in hexane. The mass ratio of the acyl groupfor every carbon number is calculated by GLC (GC-14A, manufactured byShimadzu Corp., a detector: FID, a packed column: inner diameter 3 mm×1m filler: Silicone OV-1). The mol average molecular weight (MW1) of theacyl group is calculated by using the mass ratio. Next, after apolyalcohol contained in a methanol layer is subjected to TMS, and thepolyalcohol is analyzed by GLC (GC-14A, manufactured by Shimadzu Corp.,a detector: FID, a packed column: inner diameter 3 mm×1 m filler:Silicone OV-1) to similarly calculate the mol average molecular weight(MW2) of the polyalcohol. Then, hydroxyl value (OHV) of a sample ismeasured based on a standard oil-and-fats analysis method. The averageacylation rate and the sum total of the number of the carbon atoms ofthe acyl group are calculated by the following formula.Average Acylation Rate=(168300·OHV×MW2)/{3×OHV(MWI−1)+168300}×100Sum Total of Carbon Number of Acyl Group=3×Average AcylationRate×(MW1-15)/1400

The analysis results of the plasticizers 1 to 3 and comparative samples1 to 5 were summarized in the following Table.

TABLE 1 Average Sum Total of Acylation Carbon Number Kind of PlasticizerRate of Acyl Group Plasticizer 1 55% 10.8 Plasticizer 2 84% 20.1Plasticizer 3 70% 15.0 Comparative Sample 1 45% 12.7 Comparative Sample2 70% 24.0 Comparative Sample 3 92% 15.5 Comparative Sample 4 67% 4.0Comparative Sample 5 99% 11.9 [Test-1] Tensile Test

The test was performed based on JIS K-7113. Referring to a testspecimen, a No. 1 test specimen produced by punching a sheet wasprepared and used. The produced test specimen was stored at 23° C. andthe humidity of 50% RH for one day, and the stored sample was used forthe test. As a testing machine, a tensilone universal testing machineRTC-1310 manufactured by Orientech Co. Ltd., was used. Distance betweengrip implements were set to 120 mm, and the test rate was set to 200mm/min.

[Test-2] Transparency

The shaped sheet was spread, and sheet was observed while being held upto a light source to evaluate transparency. In Table 2, ◯ denotestransparency, Δ denotes slightly white turbidity, and X denotes whiteturbidity, respectively.

[Test-3] Bleed Property

The shaped sheet was cut off to 10 cm×10 cm, and the sheet was storedunder the condition of the temperature of 50° C. and humidity of 50% forone week. The quantity of the bleed was then observed. In Table 2, ◯denotes no bleed, Δ denotes slight bleed, and X denotes considerablebleed, respectively.

[Test-4] Solvent Extraction

The shaped sheet was pressed to shape to 10 cm×10 cm×0.1 mm, and wasimmersed in n-heptane of 400 ml to extract at 25° C. for 1 hour. Afterextraction, n-heptane of 300 ml was measured, and was condensed in arotary evaporator. The condensed n-heptane was then moved to anevaporating dish, and was evaporated to dryness at 105° C. for 2 hours.The weight of the evaporation residue at that time was weighed, and thecontent of the evaporation residue to n-heptane of 300 ml wascalculated. The content of the evaporation residue exceeding 30 ppm atthis time was set to X, and the content of the evaporation residue of 30ppm or less was set to ◯.

EXAMPLES 1 TO 5

To 100 mass parts of a polylactic acid resin (Lacea H-440, manufacturedby Mitsui Chemicals, Inc.) heated and dried at 110° C. for 5 hours, massparts of plasticizers 1 to 3 shown in the following Table and 1.0 masspart of stearic acid amide were added, and were pushed out at 190° C. bya two-axle extrusion machine provided with a strand die. The strand wasthen cut to produce a pellet. The produced pellet was pushed out at 200°C. in a single axis extrusion machine provided with a T die to shape asheet having a thickness of 1 mm. The tests 1 to 4 were performed usingthe shaped sheet, and the tests were evaluated. The results weresummarized in Table 2.

COMPARATIVE EXAMPLES 1 TO 7

One using no plasticizer to the above polylactic acid resin, and oneusing the comparative samples 1 to 5 were similarly estimated as inExamples 1 to 5. The results were summarized in Table 2.

Table 2 shows the evaluation results.

TABLE 2 Tension Added Maximum Part Point Tension Added (mass StressModulus Solvent Samples part) (MPa) (MPa) Transparency Bleed ExtractionExample 1 Plasticizer 1 20 14.5 15.9 ∘ ∘ ∘ Example 2 Plasticizer 2 2015.8 16.2 ∘ ∘ ∘ Example 3 Plasticizer 3 20 21.5 18.8 ∘ ∘ ∘ Example 4Plasticizer 1 10 28.8 23.5 ∘ ∘ ∘ Example 5 Plasticizer 2 45 8.0 10.3 ∘ Δ∘ Comparative None 0 81.4 2160 ∘ ∘ ∘ Example 1 Comparative Comparative20 38.8 50.5 Δ Δ ∘ Example 2 Example 1 Comparative Comparative 20 39.549.9 Δ x x Example 3 Example 2 Comparative Comparative 20 28.6 25.8 ∘ Δx Example 4 Example 3 Comparative Comparative 20 33.5 39.9 ∘ Δ x Example5 Example 4 Comparative Comparative 20 18.6 15.8 Δ Δ x Example 6 Example5 Comparative Plasticizer 3 120 8.8 9.5 Δ x x Example 7

Though the sheet, film and molded product obtained by processing theresin composition of the present invention can be used for variousapplications such as foods, medical goods, cosmetics, manure, electricappliances, paper products, and those wastes, is possible, the sheet,the film and the molded product have favorable solvent resistance to aparaffin solvent such as hexane, heptane and a liquid paraffin. Thereby,when used for the packaging material coming into contact with oily food,the shift of the plasticizers to the food is preferably few. Therefore,the sheet, the film and the molded product are suitably used for foodssuch as green stuffs, fruits, fishes and shellfishes, meats, grains, drygoods, baked goods, dairy products, noodles, confectioneries, wildgrasses, seasonings, and as packaging materials of waste thereof.

1. An aliphatic polyester resin composition contains a compound (A) of1.0 mass part to 100 mass parts expressed by the following formula (1)as a plasticizer to an aliphatic polyester of 100 mass parts, whereinsaid aliphatic polyester resin is a lactic acid polyester,

in the formula, X denotes a trivalent polyalcohol frame; R¹, R², R³ areselected from an acyl group having 2 to 18 carbon atoms or a hydrogenatom; and where R¹, R², R³ contain at least one acyl group having 8 to18 carbon atoms, the sum total of carbon numbers of R¹, R², R³ is 10 to22; and the average acylation rate is 55 to 90% to obtain high solventresistance to a paraffin system solvent.
 2. Sheets, films, or productsmolded from the aliphatic polyester resin composition described in claim1.